With the development of information technologies, the amount of information that needs to be stored increases dramatically. The increase in the amount of the stored information promotes rapid development of the phase change memory, and also sets higher requirements for the read/write efficiency of the phase change memory.
Phase change memory (PCM) is a memory device that stores data by making use of the conductivity difference of a special material when converting between the crystalline and the amorphous states.
The basic structure of a memory cell of the PCM includes a phase change layer. The phase change layer is made of a small chalcogenide alloy, which, through central heating by an electrical pulse, can switch quickly from an ordered crystalline state to a disordered amorphous state. The electrical resistance of the amorphous state is much higher than the resistance of the crystalline state. The phase change memory stores the binary data by the difference in the magnitude of the resistivity between the crystalline and the amorphous states of the phase change layer. Specifically, the amorphous state with a higher resistance is used to store the binary “0” and the crystalline state with a lower resistance store “1”. The repetitive conversion of the phase change layer of a phase change memory from the crystalline state to the amorphous state is triggered by a melting and rapid cooling mechanism.
However, the conventional phase change memory has drawbacks of slow read/write speed and low read/write efficiency. The disclosed phase change memory and fabrication method are directed to solve one or more problems set forth above and other problems.